an international team of geophysicists for the first time found direct evidence of the presence of hydrous fluids in the upper layer of the lower mantle at a record depth of about one thousand kilometers from the Earth’s surface. A study published in the journal Lithos, briefly about it reports New Scientist.
the researchers analyzed diamond, which is approximately 90 million years ago have been thrown to the surface of the Earth near the river San Luis in modern Brazil in the eruption of the volcano. Mineral had inclusions that were in it at its formation and was found by infrared microscopy.
Inclusions in diamond were associated with the presence of hydroxyl ions, which are likely to hit the mineral with water. A detailed study of the inclusions allowed us to determine their chemical composition. It turned out that most of them consist of ferropericlase (magnesioferrite), which comprises about a fifth of the mineral phase of the lower, that is located at a depth of 660-2900 kilometers, the Earth’s mantle.
Ferropericlase consists of oxides of iron and magnesium, and may also, at high pressures and temperatures characteristic of the lower mantle, to absorb chromium, aluminium and titanium. However, these additional inclusions in the mineral was not detected, allowing the authors to conclude that the diamond appeared at a depth of about one thousand kilometers.
00:02 April 25, 2016
the Study is important for the explanation of the origin of water on the planet. The authors note that they received the world’s first direct evidence of the presence of water in such a deep layer of the mantle.
the specialists, having studied komatiite and olivine showed that at a depth of 410-660 kilometers beneath the Earth’s surface there is a canned ocean Archean period (2.7 billion years), the volume of which exceeds the size of the oceans. Their findings confirmed the work of colleagues who also investigated the hydrated minerals, particularly brucite.
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